Technical Field
Embodiments of the present invention relates to the field of display technology, and particularly to a back plate clamping device, an alignment device and an evaporation equipment.
Description of the Related Art
In OLED (organic electroluminescence) display field, currently, due to its self-luminescence property, OLED has the advantages of high visibility and brightness, low voltage demand and high power saved efficiency, quick response, lightweight, smaller thickness, simple structure and low cost, etc., and thus is regarded as one of the most promising products in twenty-first century. As being one of the OLED displays, AMOLED (active matrix organic light emitting diode) display is a device, which is manufactured by vacuum evaporating OLED material, according to certain evaporation process, onto a LTPS (low-temperature polysilicon) back plate plated with ITO (indium tin oxide), and by forming units for generations of three primary colors including R (red), G (green) and B (blue) by virtue of patterns on FMM (fine metal). This technology is now mature primarily and achieves mass productions.
During a vacuum evaporation, alignment between the FMM and the LTPS back plate should be implemented firstly. In an evaporation equipment alignment system, a back plate clamping device is used for clamping the back plate. Conventional clamping device clamps the back plate by using many finger-liked back plate clamping units, these back plate clamping units, which are independent of each other by certain distances, are fixed by bolts. After a long time use, the fixations of these back plate clamping units can be not firm enough and thus loose, which will cause lager pressure on surfaces of the back plate clamping units contacting with the back plate. Due to different degrees of tightness of the bolt fixations during the mounting, these back plate clamping units can offset, which causes partial overpressures and thus will damage the back plate during the clamping. Moreover, the LTPS back plate is prone to be broken into fragments when suffering from the increased pressure, since its thickness is of only 0.5 mm. Disposing of these fragments within the vacuum equipment is difficult and needs a prolonged fragment disposing time (of about 10 h), which greatly reduces its production capacity.